Development of any mammalian cell based protein therapeutic requires an efficient expression system. Ideally, if a multi-subunit protein (e.g., an antibody) must be produced, each polypeptide should be expressed from a single plasmid. Construction of expression vectors containing multiple genes, using commercially available expression plasmids, is problematic. Typically, the multiple cloning sites (MCS), of currently available expression plasmids, are inadequate for insertion of multiple expression cassettes. The multiple cloning sites of currently available expression plasmids contain relatively few restriction sites. Ideally, an expression plasmid for expression of multiple polypeptides would contain a large multiple cloning site containing many common and rare restriction sites.
The present invention provides, inter alia, an ideal generic plasmid expression system which can help maintain uniformity in vector construction, decrease variability in downstream processing, facilitate running multiple protein therapeutic projects simultaneously, and reduce cycle time significantly. The present invention includes such a generic plasmid platform for mammalian expression and its use for the production of various polypeptides. The platform is flexible enough to be used for expression of simple proteins, such as interferon, as well as large, complex, multi-subunit proteins, such as antibodies.